Big Hips
The opening reference by which the speaker pays homage to her hips indicates girth. Wide hips are extolled as for the space they need for moving around. This can be interpreted as a symbolic rebellion against attempts to constrict ideals of physical perfection into narrowly defined attributes.
Emancipated Hips
Speaking of rebellion, the speaker also references the history of slavery in America. The intimation based on the poet being a black woman is the speaker is also a black woman. Thus, her proud assertion of having hips that “have never been enslaved” is symbolic of enjoying the freedom and opportunity to have big hips.
Synecdoche
The speaker specifically rejects the idea of fitting into petty places as a result of the size of her hips. This is not intended to be taken literally, of course, course, nor is it designed to be applied to the hips. The hips are special type of symbolic term called synecdoche in which a single part represents the whole. Thus, the speaker’s reject of petty places is a statement of empowerment for herself against simplistic categorization.
Progressive
With the assertion that her hips do not like to be held back, the synecdoche expands to become a symbol of progressive politics. They become an ideological metaphor for the Civil Rights Movement then at its height. The speaker is suggesting that her hips swaying through the crowd is helping to make way for a changing of the status quo.
Sexuality
The attribution of powerful sexual properties to her hips capable of making a man spin like a top is another jab at convention notions of desirability which insist upon perfect symmetry of the hourglass feminine form.